Manufacture of cartridges



United States Patent [72] Inventor Bryan Hedley Hook Hackhurst Lane, Lower Dicker, Hailsham, Sussex, England [21] Appl. No. 699,082 [22] Filed Jan. 19, 1968 [4 Patented Sept. 15, 1970 [54] MANUFACTURE OF CARTRIDGES 4 Claims, 6 Drawing Figs.

[52] US. Cl 102/43, 29/ 1 .3 [51] Int. Cl. F42b 9/28 [50] Field of Search i. 102/43, 44: 29/1 .3

[56] References Cited UNITED STATES PATENTS 125,830 4/1872 Milbank 102/44 2,294,822 9/1942 Albree 102/44 2,823.611 2/1958 Thayer 102/44 2,853,945 9/1958 Stealey 102/44 OTHER REFERENCES A.P.C. Application of Tn'cou, Ser. No. 315,074. published June 22,1943.

Primary Examiner-Robert F. Stahl Attorney-Shoemaker and Mattare ABSTRACT: A rimmed or rimless cartridge case and the method of making the same which consists essentially in making, for each type, a standard shell on the one hand and as many different forms of annuli as are necessary for various uses or customers requirements on the other hand, the saleable cartridge case being completed by simultaneously securing the rim (for the rimmed cartridge case) or the head (for the rimless cartridge case) to said shell and ringing the primer or percussion cap.

Patented Sept. 15, 1970 3,528,371

FIGZ FIGS INvN Fox.

I B W Hemey HOOK H Tw lve/s" MANUFACTURE OF CARTRIDGES This invention relates to cartridge cases and to the manufacture thereof.

In accordance with one method of making a cartridge case having a rim, a shell or case is made (for example by impact extrusion) which is open at one end and which, at the closed end thereof, is provided with an annular extension, said extension constituting an axial elongation of the wall of said shell or case. Thereafter, said shell or case is subjected to a heading operation the effect of which is to cause said extension to become a radial flange or rim and the rim may then be milled for identification purposes and is then machined. The percussion cap hole or primer vent hole or vent is then formed in the bottom of the centrally located recess which is intended to accommodate said cap and the percussion cap or primer is placed in said recess and'is ringed.

This method involves a number of operations which, in total, make the manufacture of cartridges expensive, for example the costly machining operation. Furthermore, milling the radially outer surface, or a portion thereof, when such identification means are required, must be carried out on the rim which is necessarily integral with the shell or case, and the formation of the rim and the ringing of the percussion cap are necessarily separate steps in the method.

The principal object of the present invention is to simplify the manufacture of a cartridge case having a rim in order to reduce the cost thereof.

The so-called rimless cartridge case is provided with an extracting groove and a head which, in conjunction with the ejection mechanism with which any firearm adapted to use rimless cartridges is provided, enable a cartridge case to be ejected from or withdrawn from the chamber proper.

A subsidiary object of the present invention is to provide a simple method of manufacturing a rimless cartridge case as an alternative to the one or ones used at the present time.

In accordance with a first aspect, the present invention consists in a cartridge case which includes a shell or case to which a separately formed continuous annulus has been secured in order to form a rim or head.

In accordance with a second aspect, the present invention consists in a method of making a cartridge case, said method including the following steps, namely, forming a shell or case which is open at one end thereof and which has a base which is provided with at least an exterior annular flat radial surface; placing upon said surface an annulus which is continuous and which has a radially outer periphery of a diameter which is at least equal to that of the portion of said shell or case which is of the greatest diameter; and deforming a portion of said base other than said surface in such a manner as pennanently to secure said annulus to said shell or case thereby to form a rim described with reference to the accompanying drawing, in which:

F IG. illustrates an extruded shell or case which forms one part of the preferred embodiment of the present invention, the left-hand part of the FIG. being a side elevation of said shell or case and the right-hand part of the FIG. being an axial section of said shell or case;

FIG. 2 illustrates an annulus, circular in plan configuration, which forms the other part of said preferred embodiment the left-hand and right-hand parts of said FIG. being a side elevation and an axial section, respectively, of said annulus;

FIG. 3 illustrates a cartridge case having a rim (without the percussion cap or primer) made in accordance with the present invention and including the percussion cap hole or primer vent, the left-hand and right-hand parts of said FIG. being a side elevation and an axial section, respectively, of said cartridge case; and

FIGS. 4, 5 and 6 illustrate an extruded shell or case, an annulus and a rimless cartridge case, respectively, said FIGS. being similar to the views in FIGS. 1, 2 and 3,

respectively, but illustrating a different embodiment of the invention.

Referring to FIG. I, there is illustrated therein a shell or case which is indicated generally by the reference numeral 10 and which is extruded (for example by impact extrusion) from a metal blank or disc. Said shell or case 10 (hereinafter called the shell for simplicity) is, as extruded, cylindrical and open at one end to provide a mouth 11 and is closed at the other end by a base 12. The base is provided with an exterior annular flat radialsurface I3, the radially inner margin of which is defined by an axially extending boss I4 which is coaxial with said shell 10; The boss I4 is formed with a recess 15 for the accommodation of a percussion cap or primer (not illustrated), said recess being coaxial with said shell 10. The radially outer margin of said surface 13 is coincident with the radially outer surface of the cylindrical shell made by movement of a generatrix parallel to a fixed straight line.

Referring to FIG. 2, there is illustrated a circular annulus 20 which is continuous and whose radially inner periphery is of a diameter substantially equal to the diameter of the boss 14 and whose radially outer periphery is greater than the outer diameter of said shell 10.

Referring to FIG. 3, it will be seen that the annulus 20 encir cles the boss 14 and that a percussion cap hole or primer vent 30 has been formed. Said hole or vent 30, preferably coaxial with the recess 15, establishes direct communication between the recess and the space within the shell I0. The annulus 20 is permanently secured to the boss 14 of the shell 10 by suitable deformation of a part of said boss, for example by swaging or peening. The result-of said deformation isthat a V-shaped notch3l is cut in said boss near the margin thereof and that the part of said boss which is radially outwardly of said notch is swaged or peened over on to the adjacent portion of said al ls .f fl Referring now to FIGS. 4, 5 and 6 (in which the same reference numerals have been employed to indicate parts identical with or similar to those illustrated in FIGS. 1, 2 and 3, respectively), it will be seen that the base 12 is provided with the exterior annular flat radial surface 13 but that said surface has a maximum diameter which is less than the maximum outside diameter of the shell 10. It will also be seen that the annulus 20, which is continuous, has a radially inner periphery of a diameter which is substantially equal to the diameter of the boss 14 and has a radially outer periphery of a diameter which is not greater than the maximum outside diameter of the shell 10. Consequently, when the shell 10 and the continuous annulus 20 have been permanently secured to one another by swaging or peening or in any other suitable manner, an extracting groove 50 will have been formed, the annulus 20 thus secured being known as the head of the rimless cartridge shell or case.

The main advantages of making a cartridge case in the manner described above are as follows:

I. Ringing of the percussion cap or primer and securing the annulus 20 to the boss 14 in the manner explained above are effected simultaneously in a single operation;

2. Milling of the radially outer peripheries of all annuli, when such milling is required for identification purposes, is done before the annuli are secured to the shells. Therefore, it is possible to manufacture shells for stock which are common to all annuli regardless of the milling or absence of milling on those annuli; and

3. When impact extrusion is employed in preference, for example, to drawing, the extruded shell or case does not need any finishing operations to be performed by machine turning, or any other forming operation.

These advantages lead to considerable economies which result in reductions in cost of as much as 30 percent.

The shells or cases may be made of metal or of a synthetic resin material.

I claim:

1. A two piece rimless cartridge case comprising:

a. a one piece shell consisting of a cylindrical side wall por tion open at one end thereof and closed at the other end by a base portion integral with the side wall portion, said base portion having a thickness dimension axially of the shell which is substantially greater than the thickness of said side wall portion, said base portion having a stepped periphery consisting of a first portion thereof of less diameter than the outer diameter of said side wall portion and a second portion thereof of less diameter than said first portion, the step in said periphery joining said first and second portions, being flat, being disposed with its plane normal to the shell axis and forming an annular rearwardly directed shoulder on said base portion, and said base portion being formed on the underside thereof with a recess for the reception of a percussion cap or primer; and

b. a rigid flat annulus whose outer diameter is not greater than the outer diameter of said side wall portion and whose inner diameter is not less than that of said second portion of said stepped periphery, while being less than the diameter of said first portion of said stepped periphery, said annulus being fitted over the smaller diameter portion of said base portion in abutting relation to said shoulder, and an annular lip on said base portion upset over the inner margin of said annulus rigidly holding the annulus in this position, the outer margin of said annulus constituting the head of the case.

2. A cartridge caseaccording to claim 1 wherein said lip is constituted by the radially outer wall of a rearwardly open annular V-section notch in the peripheral underside of said base portion.

3. A method of making a cartridge case, said method including the steps of:

a. forming a one piece shell or case with a cylindrical side wall portion open at one end thereof and closed at the other end by a base integral with said side wall and having a thickness dimension axially of the shell which is substantially greater than the thickness of said side wall portion;

b. providing said base with at least an exterior annular flat radial surface;

c. forming a boss on said base of only slightly less diameter than said base and which is a constituent part of said base during the step of forming said shell or case, said boss defining the radially inner margin of said surface;

d. placing upon said surface an annulus which is continuous and which has a radially outer periphery of a diameter which is at least equal to that portion of said shell or case which is of the greatest diameter;

e. deforming a portion of said base by cutting a rearwardly open V-section notch in the peripheral underside of said boss and swaging or peening that part of said boss which g. cutting an annular rearwardly is radially outwardly of said notch on to the adjacent portion of said annulus to hold said annulus in position on said surface;

f. forming a rearwardly or outwardly facing percussion cap or primer recess in said base during the step of formation of said shell or case;

g. forming a hole in the bottom of said recess, said hole placing said recess in communication with the space within said shell or case;

h. placing a percussion cap or primer in or in axial alignment with said recess;

i. simultaneously ringing said percussion cap or primer with the cutting of said notch and swaging or peening of said part; and

j. milling the radially outer periphery of said annulus before said annulus is placed upon said surface preparatory for being secured to said shell or case.

4. The method of making a two piece rimless cartridge case comprising the steps of:

tion having a cross-sectional thickness dimension axially of the shell which is substantially greater than the cross sectional thickness of said side wall portion;

c. forming said base portion with a stepped periphery;

d. making the first portion of said stepped periphery of slightly less diameter than the outer diameter of said side wall portion and a second portion thereof of less diameter than said first portion, the step in said periphery joining said first and second portions, being flat, being disposed with its plane normal to the shell axis and forming an annular rearwardly directed narrow shoulder on said base portion;

e. forming a recess for the reception of a percussion cap or primer on the underside of said base portion;

'iffiiirigfii id flatannulus whose outer diameter is not I greater than the outer diameter of said side wall portion and whose inner diameter is not less than that of said second portion of said stepped periphery, but is less than the diameter of said first portion of said stepped periphery over the smaller diameter portion of said base portion in abutting relation to said shoulder;

'p'n axial notc h ifsaid smaller diameter portion of said base; and

I hrswaging or peening that portion of said base which isradially outwardly of said notch over the inner margin of said annulus, the outer margin of said annulus constituting the head of the case. 

